Field of the Invention
This invention pertains to a multi-processor system having multiple processors arranged in a moving object or in multiple moving objects and the method of processing data in said multi-processor system.
Recently, electronics applications in moving objects such as automobiles have increased in order to achieve greater ease of operation, operational stability, safety and comfort. As more sophisticated control is attempted, however, the number of sensors, controllers and actuators mounted on the moving object increases and the size of the wire harness connecting them also increases accordingly. This increase in harness size not only increases the weight of the moving object but also increases the difficulty of installing wires and causes many problems such as response delay between the sensor and actuator and reduced reliability. In recent years, networking in a moving object has been tried in order to reduce the harness size. But a moving object such as an automobile comes in a variety of model types and therefore modifications occur frequently. Because they are exported to many countries all over the world, the moving objects must be modified to suit the regulations and weather conditions of various countries. For a moving object, safety is the first concern, and ease of operation and comfort are also important product features.
Therefore, for reasons of safety, high reliability and fault tolerance (capacity to continue operating correctly when a fault occurs) are demanded of the network multi-processor system; expandability, that is, ease of adding and removing a processor (controller) is demanded to accommodate various model types, modifications for exports and improvement in quality. Additionally, in order to attain good serviceability, the parts must be easily replaceable by removal and insertion when a fault occurs.
In a conventional multi-processor system in a moving object, each processor in the system specifies the address of the receiver when transmitting data. Thus, if the structure of overall system is not yet determined if the structure changes due to an addition removal of problem within a processor, the address needs to be redefined or a problem in part of the system often stops the overall system operation. Conventionally, realization of a network multi-processor system to increase reliability requires special hardware and software and if a problem occurs, a procedure to activate a backup system is necessary, thereby bringing about many problems in terms of cost and response.
The conventional data flow type program does not run unless all input data are present. In the conventional multi-processor system in a moving object, each processor in the system specifies the address of the receiver when transmitting data.
Thus, the relationship between the transmitting and receiving processors must be predetermined, so that the relationship between individual processors becomes closer. For this reason, when the system configuration is undefined or changed, the relationship between the transmitting and receiving processors must be redefined, which affects the overall system. When a multiplicated system is implemented, special hardware and software are required and this is an unacceptable problem in terms of cost. When the control software is data-flow-type, the software is not actuated until all input data are received, and when data is missing for any reason, important software is not driven.